Anode Heel Effect Flashcards
anode heel effect
radiographic phenomenon affecting the intensity of the x-ray beam causing x-ray photons to be absorbed
the anode angle will increase the surface area of the ______ _____ and will therefore increase the ability of anode to _________ _____.
focal spot
absorb heat
the anode angle will decrease the _____ size which will increase ________ ___________.
EFS
spatial resolution
a larger number of x-ray photons will be produced at the cathode side of the x-ray tube due to what?
the angle of the anode
Why does the cathode side have a higher intensity than the anode side?
the absorption of the photons deep in the anode heel
What produces the anode heel effect?
a number of photons deep in the anode never escape the target so they are absorbed in the anode heel
variables affecting anode heel effect
SID
anode target angle
image field size
The relationship between the anode heel effect and the SID is what?
indirect
What does less angle mean?
more anode that a photon needs to escape to become part of the beam
What does more angle mean?
less anode that a photon needs to escape to become part of the beam
The relationship between the anode angle and anode heel effect is what?
indirect
The relationship between the field size and anode heel effect is what?
direct
What can happen when the anode heel effect causes a variation of intensity of photons across the x-ray field?
uneven exposure to the IR
FAT CAT
place the thickest part of the patient underneath the cathode end of the x-ray tube
Why do you place the thickest part under the cathode end?
it will provide a greater number of photons to penetrate and image the thicker parts
What can the heel effect be used effectively for in radiography?
femur
lower leg
humerus
thoracic spine
and lumbar spine
Which of the following will decrease the anode heel effect?
A. Decrease SID, increased field size, and increased anode angle
B. Increase SID, decreased field size, and decreased anode angle
C. Decrease SID, increased field size, and decreased anode angle
D. Increased SID, decreased field size, and increased anode angle
D. increased SID, decreased field size, and increased anode
Define exit beam
beam that is exiting the patient to the IR
Define useful beam
beam exiting the tube that is heading towards the patient
What SID will lead to increased anode heel affect?
the smallest
The anode heel effect causes what 2 things?
variation of beam’s intensity across field
a greater intensity of x-rays on the cathode side
Increased x-ray photons on the cathode side of the beam describes:
the anode heel effect
What will occur when the angle of the anode increases?
increased ability in anode to absorb heat
decreased anode heel effect
decreased spatial resolution
What SID will lead to a decreased anode heel effect?
the highest amount
Increasing the field size will result in:
increased anode heel effect
What factors will increase the anode heel effect?
decreased SID
increased field size
decreased anode angle
What factors will decrease the anode heel effect?
increased SID
decreased field size
increased anode angle
The use of an x-ray tube with a large anode angle results in which two of the following?
increased heel effect
increased focal spot size
increased heat capacity
decreased heat capacity
increased focal spot
increased heat capacity
The anode side of the x-ray field demonstrates:
lower intensity
What is the anode heel effect caused by?
x-ray absorption within the anode
Directing the anode side of the tube towards the toes in an AP projection of the foot results in:
more uniform receptor exposure
The use of an x-ray tube with a small anode angle results in which two of the following?
decreased heel effect
decreased focal spot size
increased focal spot size
decreased heat capacity
decreased focal spot size
decreased heat capacity
What exposure modification will increase the anode heel effect?
decreased SID
the cathode side always has what than the CR?
a higher intensity
Which of the following is a potentially negative consequence of an increased anode angle?
decreased effective focal spot
decreased anode heel effect
increased effective focal spot
increased anode heel effect
increased effective focal spot
an increased effective focal spot size will lead to:
decreased spatial resolution
Which of the following occurs when the anode angle decreases?
EFS size decreases and heel effect decreases
EFS size decreases and heel effect increases
EFS size increases and heel effect increases
EFS size increases and heel effect decreases
EFS size decreases and heel effect increases
